It is generally known to a person skilled in the art of rolling bearings that single-row grooved ball bearings are rigid undismountable radial rolling bearings which are distinguished, above all, in that their radial and axial load-bearing capacity is equally high, and that, because of their low friction, they have the highest rotational speed limits of all types of bearing. These grooved ball bearings have been known for a long time and consist essentially of an outer bearing ring and of an inner bearing ring and also of a number of balls arranged as rolling bodies between the bearing rings. Into the inside of the outer bearing ring and into the outside of the inner bearing ring, respectively, groove-shaped ball raceways are machined in which raceways the balls are guided in a bearing cage at uniform distance to each other. Radial ball bearings are filled with the balls by means of the eccentric mounting method which became known from DE 168 499 and in which the two bearing rings are arranged eccentrically to one another, and the free space occurring as a result between the bearing rings is filled with the balls. The size and number of the balls are dimensioned according to the bearing size such that the inner bearing ring between the first and the last ball can be brought, using the elasticity of the two bearing rings, into the position concentric with respect to the outer bearing ring, so that the balls can finally be distributed at a uniform distance from one another on the reference circle of the two ball raceways and the bearing cage can be inserted.
It became apparent in practice, however, that grooved ball bearings of this type nevertheless have defined limits in terms of the load-bearing capacity of the bearing because of the small maximum installable number of balls which depends on the dimensions of the inner and of the outer bearing ring and also on the ball diameter. In the past, therefore, a multiplicity of solutions were proposed, by means of which an increase in the load-bearing capacity of grooved ball bearings was to be achieved by means of an increase in the number of balls.
Thus, for example, it has already been proposed by DE 151 483 to arrange on one side of the grooved ball bearing, in the mutually opposite rims of the outer and of the inner bearing ring, a clearance as a filling orifice, which corresponds to the shape of the balls and through which the balls can be introduced into the bearing without interspaces with respect to one another and can be distributed. However, as a rule, this filling orifice remains unsealed and therefore has the disadvantage that the balls always have to run past this filling orifice during operation. Particularly in grooved ball bearings, in which the filling orifice then issues in the form of a wedge into the raceways of the balls, however, the result of this is that a “catching” or jamming of the rolling bodies at this filling orifice may occur, particularly, when axial forces press the balls against the rims of the bearing which are provided with the filling orifice.
Even the solution, disclosed by DE 24 07 477 A1, to reclose the filling orifice in the rims of the bearing rings, after the filling of the rolling bearing with the rolling bodies, in such a way that the closing pieces, broken out of the rims of the bearing rings beforehand via a milled predetermined breaking notch are inserted into the rims again by adhesive bonding or welding, has not proven appropriate, in practice, since, by the closing pieces being adhesively bonded or welded, adverse burrs or adhesive surpluses are formed on the rim guide surface and may cause, as before, such a “catching” of the rolling bodies. Furthermore, the connection point of the closing pieces always constitutes with respect to the remaining rim a weak point in terms of their strength, so that rolling bearings of this type can be subjected to only a limited axial load in one direction at least.
Another possibility for increasing the number of rolling bodies on a radial rolling bearing became known, furthermore, from DE 43 34 195 A1. In this radial rolling bearing designed per se as a single-row grooved ball bearing, however, the rolling bodies are not formed by balls, but, instead, either partially or completely by what are known as spherical disks which are designed with two side faces flattened symmetrically from a basic spherical shape and arranged parallel to one another. The width of these spherical disks between their side faces is smaller than the distance between the inside of the outer bearing ring and the outside of the inner bearing ring, so that, when the bearing is being filled, the spherical disks can be introduced into the bearing axially with respect to the bearing through the clearance between the inner ring and outer ring. When the center point of the spherical disks is then located level with the rolling body raceway axis, the spherical disks are rotated by 90°, so that they can roll with their spherical surfaces in the rolling body raceways.
Despite the possibility of inserting the specially designed spherical disks axially into the bearing and therefore being able to fill the radial rolling bearing almost completely with a high number of rolling bodies, such a radial rolling bearing is nevertheless, at most, only a compromise in terms of the desired increase in load-bearing capacity of the bearing. This is because the spherical disks, on account of their capability of axial introduction into the bearing, have only a correspondingly narrow design or a design with a correspondingly small width between their side faces, so that they can easily be introduced into the bearing through the clearance between the inner ring and outer ring. Likewise, the rolling body raceways in the bearing rings can have only a relatively shallow and narrow design, so that the rotation of the rolling bodies into their operating position can be made possible, without too high a radial play in the overall bearing occurring in this operating position. However, the relatively narrow spherical disks and the shallow rolling body raceways give rise to a relatively small contact area of the spherical disks with their rolling body raceways, so that both the axial and the radial load-bearing capacity of such a radial bearing is again reduced and the original advantage of the increased number of rolling bodies is virtually compensated.